Francis Wayland Thurston
Francis Wayland Thurston is a prominent resident of Boston who, following his grand-uncle's sudden and baffling death, discovers and investigates the Cthulhu Cult. Thurston writes the manuscript that is "The Call of Cthulhu" based on his findings in his grand-uncle's belongings and his own follow-up discoveries. The transcript is broken into three parts: "The Horror in Clay," which explains his grand-uncle's death and Thurston's discovery of his belongings, as well as the story of Henry Anthony Wilcox, a hyper-sensitive sculptor; "The Tale of Inspector Legrasse," which recounts a police inspector's encounter with the Cthulhu Cult; and "The Madness from the Sea," in which Thurston discovers the diary of second mate Gustaf Johansen. Thurston ends the story predicting that he will be killed for what he knows, and the title indicates he has died.
George Gammell Angell
George Gammell Angell is a Professor of Semitic Languages in Brown University, Providence, Rhode Island. He is also Thurston's grand-uncle. Angell dies of sudden and mysterious causes, which results in Thurston's discovery of his belongings surrounding the Cthulhu Cult. Thurston describes Angell as "an authority on ancient inscriptions," which is why Wilcox sought him out following his dreams of Cthulhu. Through Angell, Thurston learns about the testimonies of Inspector Legrasse and Henry A. Wilcox. Over the course of the story, Thurston increasingly suspects that Angell was murdered.
Henry Anthony Wilcox
Henry Anthony Wilcox is a student of sculpture at the Rhode Island School of Design who visits Professor Angell's office bearing a small clay bas-relief shaped like Cthulhu. Although from a prominent family, Lovecraft describes Wilcox as a "queer" and "hyper-sensitive" boy whose eccentricity caused him to fall out of social favor with his friends and family. Wilcox matures into a decadent sculptor who specializes in recreating the otherworldly imagery from the dreams he reports to Angell. Wilcox's dreams are the first glimpses the reader receives of the world of the Cthulhu cult, and cause Angell to record the dreams of other poets and artists.
John Raymond Legrasse
John Raymond Legrasse is a police inspector that witnessed the Cthulhu cult performing a mass human sacrifice ritual firsthand. While investigating the disappearances of several women and children on the outskirts of a southern Louisiana town, Legrasse participates in a police raid and finds the charred remains of several townspeople in an all-male Cthulhu Cult ritual in the swamp. Legrasse travels to St. Louis to show Professor Angell and other experts a statuette recovered from the raid, and compares his phonetic transcriptions of ritual chants with another professor's. Legrasse provides the key testimony of Old Castro, an elder cultist apprehended in the raid, who rambles about "Great Old Ones" and the kind of "Cyclopean" cities also imagined by Wilcox.
Gustaf Johansen
Gustaf Johansen is the second mate of a two-masted schooner named the Emma. As Thurston reads in news item, the Emma is attacked by a yacht named the Alert, leaving Johansen in charge of the vessel. Johansen orders his crew to board the Alert and sail to a small island where everyone but Johansen perishes. Johansen gives no details to the Sydney Bulletin about what transpires when the men reach the island, and it is only from Johansen's personal diary that Thurston learns that the men actually reached "the nightmare corpse-city of R'lyeh" and awakened Cthulhu. Johansen dies after having a stack of papers dropped on his head, and Thurston suspects that he is murdered.
Old Castro
Old Castro is an elder Cthulhu cult member, apprehended in a raid on a voodoo ritual, who Legrasse remembers as being especially lucid and compelling in his testimony about the origins of the cult. Legrasse recalls to Angell and others that Old Castro spoke of "Old Ones" and "Things"—massive creatures that preceded humanity and lived in giant Cyclopean cities. Old Castro also alleges that these "Old Ones" are from outer space, a fact that Thurston remembers at a critical juncture when pondering Johansen's geologically foreign stone idol. Old Castro dies before Thurston can travel to Louisiana to interview the other prisoners apprehended in the raid.
William Channing Webb
William Channing Webb is a professor of Anthropology at Princeton University, present at the American Archaeological Society meeting where Legrasse reveals his statuette. Webb reports to Legrasse, Angell, and the other men that he once came across a similar statuette on the west coast of Greenland while collecting data on the oral rituals of an Inuit tribe. It is only with Webb's phonetic transcriptions that the men are able to do a comparative analysis with Legrasse's data and decrypt the letter formations, "Cthulhu" and "R'lyeh."
Joseph D. Galvez
Joseph D. Galvez is the name of a New Orleans policeman who Legrasse mentions as having an especially peculiar testimony about the police raid on the voodoo ritual at the swamp. Galvez, Legrasse remembers, insists that he heard the sounds of gigantic beating wings out in the forest. Galvez's description correlates with the testimony of many of the cult members, who tell Legrasse that they were ordered by "Black Winged Ones" to commit the crimes.
Abdul Alhazred
Abdul Alhazred is the name of an Arab mystic invoked by Old Castro. In the mythology of Lovecraft's fiction, Alhazred is the author of the Necronomicon—a grimoire, or book of curses. Old Castro guesses that the original earthly center of the "Old Ones" is somewhere in the Arabian desert.
Briden
Briden is the name of the sailor who is found dead aboard the Alert when the Vigilant tows the ship into Darling Harbour. According to Johansen's diary, Briden is the only other man who makes it back to the ship alive after the men unknowingly awaken Cthulhu from his monolithic resting place. However, Briden succumbs to madness and delirium after witnessing Cthulhu, and expires before the Alert makes it back to the mainland.
